None
Not applicable.
The present invention relates generally to high-pressure apparatuses and more particularly to a ring design that minimizes ring failures.
Conventional high pressure/high temperature (HP/HT) apparatuses, which may be of the belt-type or die-type, are described, for example, in U.S. Pat. Nos.; 2,941,241; 2,941,248; 2,947,617; 3,609,818; 3,767,371; 4,289,503; 4,409,193; 4,673,414; 4,810,479; and 4,954,139, and French Pat. No. 2,597,087, the disclosures of which are expressly incorporated herein by reference. It is not uncommon for these types of HP apparatuses to contain on the order of 800,000 to 1,000,000 psi. Materials of construction and tooling design permit such pressures (as well as high temperatures, say, on the order of 2,000xc2x0 C.) to be generated for preparation of diamond, cubic boron nitride (CBN), hexagonal boron nitride (HBN), and the like.
A series of rings (belt set) or wound containers are used to confine the contents (e.g., graphite when diamond is being made and boron nitride when CBN is being made) being subjected to such high pressures, which normally are created by punches or dies. A rounded or radius corner has been applied to such rings in order to avoid galling during the assembly of the inner ring and to eliminate a sharp edge for worker safety. Unfortunately, such a radius corner creates tensile stresses, which leads to fatigue failure. Failure of the ring causes a local loss of tooling, not to mention loss of product and down time to assemble new tooling for the HP apparatus. By eliminating tensile stresses and maintaining only compressive forces, such ring failures would be less likely to occur.
Thus, there exists a need in the art to design inner HP rings that do not create tensile stresses with subsequent ring fatigue failure. It is to such need that the present invention is addressed.
Unexpected, it has been discovered that the inner annular binding ring""s inner upper edge has an area that is under tensile stresses. By removing the ring material under tensile stresses, the propensity of the inner binding ring to fracture is significantly lessened. Such binding ring material can be conveniently removed by chamfering the inner upper edge of the inner annular binding ring at an angle of greater than about 60xc2x0 from the vertical. The remaining ring material is under compressive stresses and is less likely to fracture during the high-pressure operation. Such chamfering operation creates a transition slope that mitigates tensile stresses.
The invention, then, is high-pressure apparatus (belt/die, pre-tensioned loaded windings, or other configuration) which has a series of annular binding rings for confining material being subjected to high-pressure treatment. The series of annular binding rings has an inner annular binding ring having an inner upper edge, an outer upper edge, an inner lower edge, and an outer lower edge. The inner lower edge is chamfered at an angle of greater than about 60xc2x0 from the vertical.
Advantages of the present invention include the ability to lessen fatigue failures of inner annular binding rings of HP apparatuses. Another advantage is the ability to achieve such fatigue failure lessening by a machining operation. A further advantage is that the chamfered inner ring still is worker safe. These and other advantages will be readily apparent to those skilled in the art.